窄带隙Pr_(0.6)Ca_(0.4)MnO_3体系的电荷有序和多重磁化转变  

CHARGE-ORDERING AND MULTIPLE MAGNETIZATION TRANSITIONS IN THE NARROW-BANDWITH COMPOUND Pr_(0.6)Ca_(0.4)MnO_3

作　　者：沙燕娜[1] 张金仓[1] 曹桂新[1] 康保娟[1] 姚恺[1] 曹世勋[1] 敬超[1] 

机构地区：[1]上海大学物理系,上海200436

出　　处：《低温物理学报》2005年第A01期445-451,共7页Low Temperature Physical Letters

基　　金：国家自然科学基金(No.10274049);上海市科委基础研究重点项目(No.04JC14039);上海市教委曙光计划(No.03SG35);上海市教委重点学科建设项目的资助~~

摘　　要：研究了窄带隙Pr0.6Ca0.4MnO3体系的电荷有序及低温下的团簇玻璃现象.实验表明,样品具有典型的相分离特征,在高温区于241K左右发生电荷有序(Charge Ordering,CO)转变,在高的外加磁场下破坏了样品的电荷有序和反铁磁,使材料发生绝缘-金属转变.在低温下(T^41K),形成自旋玻璃态(Spin Glass,SG).发现了存在于低温团簇玻璃相中的多重磁化跳跃现象,利用外场作用下AFM团簇中磁矩的翻转而导致铁磁成分的增加对实验结果给予了初步解释,证明了磁场作用对Pr0.6Ca0.4MnO3的CO与团簇玻璃态冻结之间的直接关联作用.In this paper, we study the charge ordering （CO） and the cluster glass （CG） state at low temperature in the narrow-bandwith compound Pr0.6Ca0.4MnO3. It shows that the sample possesses a typical characteristic of phase separation. The CO transition takes place at about 241K. Applied magnetic field will weaken its CO state and the anti-ferromagnetic （AFM） ordering, inducing an insulator-metal transition. When T is around 41K, it forms a spin glass phase. The multiple magnetization jumps are found in the cluster glass phase at low temperature. Because the magnetic moments in the AFM clusters will reverse under the external field and lead to an increase of ferromagnetic components, so we indicate that the field has a direct correlation with the CO state and the freezing of CG state in Pr0.6Ca0.4MnO3.

关 键 词：电荷有序 团簇玻璃态 多重磁化跳跃 

分 类 号：O482.5[理学—固体物理]